This invention relates to a resiliently deformable plug capable of occupying a sealing position in a shaft having larger and smaller diameter sections, the plug being capable of passing from the larger diameter section through a smaller diameter section.
Some automotive drive shafts have a relatively large diameter section portioned between relatively small diameter end sections. Many such shafts require the positioning of a damper in the larger diameter section for absorbing vibrations and attenuating noise. In some instances the ends of the shaft are reduced in diameter by a swaging operation for the purpose of enabling universal joints or other devices to be joined to the reduced diameter ends of the shaft. Normally, the damper is positioned in the shaft prior to the swaging operation. In some cases the damper is formed of paper or other hygroscopic materials.
Following the swaging operation it is conventional to wash the ends of the shaft to remove the swaging compound and to machine the free ends of the shaft to provide them with smooth and planar end surfaces which, in some instances, may be beveled. If the damper is formed of materials which may be damaged by water or chips generated in the machining operation, care should be taken to prevent such damage.
One example of protecting the damper against such damage is disclosed in U.S. Pat. No. 5,976,021. Another example is disclosed in application Ser. No. 09/572,767 filed May 17, 2000. The invention disclosed herein constitutes another approach to protecting the damper against damage.
Apparatus constructed in accordance with the preferred embodiment of the invention comprises a sealing plug which is capable of being inserted in a drive shaft of the kind that subsequently will have its ends reduced by a swaging operation following which the ends of the shaft will be washed and machined. The plug may be positioned in the shaft inward of or at that part of the shaft that is to be reduced in diameter. In either case, the plug will prevent the passage of any water or chips to the damper and may be withdrawn from the shaft through the reduced diameter ends when the plug no longer is needed.
The plug comprises a central, cylindrical core having a bore therethrough in which is accommodated a force transmitting rod terminating at one end in an eye. Extending laterally and outwardly from the core is a conical web that is joined at its outer end to a cylindrical skirt which encircles the core. The core, the web, and the skirt are formed of closed cell, resiliently deformable foam material which enables the plug to be radially expanded and contracted sufficiently to enable the plug, in its expanded condition, to seal an end of the shaft and be withdrawn, when desired, through the reduced diameter end of such shaft.
A plug constructed in accordance with the invention is capable of use in conjunction with drive shafts of considerably different diameters and is reusable.